Problems with Corona AO map

[JoachimArt]

I I'm using the Corona AO map for edge wear etc. But I have a problem whenever I really want the edges to have a strong contrast between the two materials or colors that AO-map generates AO on all lines and edges even on flat surfaces. I often have a problem with this on cylinders but also in some cases on flat faces. Since Corona currently don't a have a curvature map, It would be really awesome if there were some way of controlling the minimum curve treshold, but I haven't found a way yet.

Please help.

[sprayer]

I am also struggle from this everywhere. You can try to tweak ray directionality but it also change a bit brightness

[JoachimArt]

Yeah I found out it helps slightly but not much :( and as you say it makes the edge weaker.
It’s sad because it’s so hot to be able to control edge masks to make quick materials without going through substance painter or similar, but corona ao has a lot of limitations.

I was really bummed out to see that curvature map was removed from the roadmap for the next release, for me that feature would have been more appreciated than everything else planned for v.6.
Please corona team! Fix AO or add curvature control map soon 😉

[sprayer]

You may try to use round edge bump map as mask instead AO it may help sometimes

[maru]

Ray directionality should really help here. Can you share an example (simple) scene?

[JoachimArt]

Hey thanks for the replies.
Maru, sure here's an example scene attached. It becomes more prominent on dark materials and metals than white. So, I made the material dark, with white you can hardly see the problem. And its not always a problems except when you want to exaggerate edges.
But on these models I cannot make the edge disappear from the flat surface and the cylinder, no matter how I change directionality (you can make it disappear on the cylinder but then the hard edge AO almost disappear too). Also it's impossible to have a thin edge line with completely opaque/hard color with Corona AO, its almost always a slight blend between the two colors on the edge (even with a color correction layer on the AO)

sprayer, thanks! Yeah round edges works as long as there's no chamfer or soft edge, too bad, if it had worked with multiple angles, not only hard edge, it would have been a perfect Curvature map. I can't think that could be a hard material to make based on that (corona team?) - just add a treshold/max min curve

[maru]

How about something like this?
The Corona Color Correct map has gamma 0.45 to make the AO gradient more linear.
Then the gradient is boosted using a 3ds Max Output curve.
Maybe splitting the "inside" and "outside" modes of the AO and then combining them back using Corona Mix would be a good idea too. Otherwise they kind of negate each other and the result is hard to control.
I am just not entirely sure what exact effect you are after.

[JoachimArt]

Thanks! that is a better result than I managed, though the curvature on the smaller corner kind of disappear. What I am trying to achieve is very exaggerated hard corner material switch. Because I'm modelling small tech parts for a game (type starcraft 3 style), and since the objects are small its important to exaggerate the edges a lot, so the shader is probably not meant for this (which is why I'm hoping Corona can make a more reliable Curvature map in the future, similar to what Vray and Redshift has). But I have made the objects and was able to hack around it like you did now, but it's not an optimal solution. Attached images is how I use it (you see the weak tint of edges there a that are not suppose to be visible, but its vague so it's ok, but I just wish I could easily achieve this without workarounds)